PH and PPMs are paramount in my opinion. Obviously overwatering is important. Which is one of the reasons I love coco. That being said I check the weight of my pots/know when they need it.
On the second tough when I had a closer look at the plant and the purple edges remind me of ghost mites. I had once I had to delude sulfuric acid in with bleach 3:10 you can also add 2 caps of n2o2 and Epsom salt to help it recover. You should spray the mix upon all the leaves during the light cycle. They should be gone by the end of the light cycle.
I havent been able to take any pictures recently but heres one from about a week ago. Dont mind the dirty mechanic hand lol. The 6 inch tall plant was successfully topped. And my gdp has finally sprouted.